package day04;

import java.util.Collection;
import java.util.HashSet;

public class Demo04 {

	public static void main(String[] args) {
		Collection col = new HashSet();
		boolean b = col.add("Jerry");
		System.out.println(b);

		b = col.add("Tom");
		System.out.println(b);

		b = col.add("Tom");
		System.out.println(b);
		System.out.println(col);


		b=col.contains("Tom");
		System.out.println(b);

		b=col.contains("tom");
		System.out.println(b);
		
		b=col.add(new Person("PPT",67));
		System.out.println(b);
		
		System.out.println(col);
		
	
	}

}
